The Pressure-based solver offers an improved treatment of symmetry and periodic boundaries for the node-based gradient. The treatment is controlled by first enabling beta feature access, and using the text-command.

solve/set/nb-gradient-improved-symmetry-periodic? yes/no

In the density-based solver, the treatment does not require beta feature access, and is engaged by default. For details, see Green-Gauss Node-Based Gradient Evaluation in the Fluent Theory Guide.